Download INFERENTIAL STATISTICS (Ch. 9-13)

INFERENTIAL STATISTICS (Ch. 9-13)
Proportions
Means
Statistics & Parameters:
Statistics & Parameters:
Requirements:
(1) Independence: sample is less than 10% of population
(2) Approx Normal: np  10 and n 1  p   10
(3) SRS: stated or assumed
Requirements:
(1) Independence: sample is less than 10% of population
(2) Normal:
*Population is Normal as stated in problem
*By CLT n > 30 approx normal
*Normal Probability Plot is linear approx normal
*Box Plot appears symmetric approx normal
(3) SRS: stated or assumed
Test Statistic:
Test Statistic:
pˆ  ?
p?
z
statistic - parameter
standard deviation of statistic
x ? s?
 ?
t
statistic - parameter
standard deviation of statistic
Chi-Square
Linear Regression
Requirements:
(1) Expected Value: each expected cell count  5
(2) SRS: stated or assumed
Requirements:
Linear regression is appropriate
Test Statistic:
Test Statistic:
 
2

(observed-expected)2
expected
t
statistic - parameter
b0

standard deviation of statistic
sb
Confidence Interval
point estimate  margin of error
Statistic  (critical value)  (standard deviation of statistic)
Interpret the Interval:
We are 95% confident that the true proportion (mean) of _________________is between ___ and ___.
Interpret the Confidence Level:
In repeated sampling, approximately 95% of the intervals produced using this method will contain the true proportion
(mean).
Calculator:
1-Prop Z interval
T-interval
Hypothesis Test
8 step procedure for a hypothesis test:
1) State the population characteristics of interest.
2) State the null hypothesis H 0 .
3) State the alternative hypothesis H a .
4) State the significance level.
5) Name the Test and state the requirements required for the test.
6) State the test statistic (t or z) and compute its value.
7) Determine the P-value.
Reject H 0 if
Fail to reject H 0 if
P-value  
P-value > 
8) State a conclusion in the context of the information given in the problem.
Conclusion:
There is/is not convincing evidence [Step 1], [Step 3].
Interpret p-value
Given the null hypothesis were true, the probability that the observed statistic, or more extreme, could occur.
Calculator:
Z Test, T-Test, 2-samp Z Test, 2-samp T-Test, 1-Prop Z Test, 2-Prop Z Test,  2 Test, Lin Reg T Test